The impact of pre-natal stress on offspring development in pigs

Abstract

SUMMARYIn farm animals, restricted housing conditions or inadequate management practices during gestation may be potential stressors for the mother, with possible consequences on the growth, vitality, health and welfare of the dam and its offspring, and thus can have economic as well as ethical implications. The current review summarizes data from studies in pigs on the impact of maternal stress during gestation on the litter characteristics and phenotypic traits of offspring. The outcomes from the different experimental models using either maternal stress paradigms or artificially increased maternal cortisol are presented, and possible reasons for the consistent or divergent results are discussed. Maternal stress models are of particular importance, because social stress, restraint, rough handling and heat or cold stress are of practical relevance during housing of pregnant sows, whereas in other models the specific role of maternal cortisol as a mediator for pre-natal stress is studied. The data reveal that pre-natal stress in pigs can impair growth and modify the immune function, stress reactivity and behaviour of offspring. There is evidence that the materno-foetal cortisol regulation is a major determinant of the alterations in offspring. Neuroendocrine and behavioural data in the offspring indicate that pre-natally stressed pigs can express a modified phenotype characterized by increased reactivity of the hypothalamic–pituitary–adrenal axis, altered emotionality, more fearfulness in a novel environment and disturbed social and maternal behaviour. Further research is needed and should focus on the long-term consequences on immune function, reproductive traits and maternal behaviour in female offspring used as breeding animals.